Hib vaccine

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Hib vaccine
Hib for infanrix hexa.jpg
Hib component of Infanrix hexa
Vaccine description
Target Haemophilus influenzae type b
Vaccine type Conjugate
Clinical data
Trade names ActHIB, Hiberix, OmniHIB, others
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MedlinePlus a607015
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Hib vaccine
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The Haemophilus influenzae type B vaccine, also known as Hib vaccine, is a vaccine used to prevent Haemophilus influenzae type b (Hib) infection. [2] [3] In countries that include it as a routine vaccine, rates of severe Hib infections have decreased more than 90%. [2] It has therefore resulted in a decrease in the rate of meningitis, pneumonia, and epiglottitis. [4]

Contents

It is recommended by both the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC). [2] [5] Two or three doses should be given before six months of age. [2] In the United States a fourth dose is recommended between 12 and 15 months of age. [6] The first dose is recommended around six weeks of age with at least four weeks between doses. [2] If only two doses are used, another dose later in life is recommended. [2] It is given by injection into a muscle. [2]

Severe side effects are extremely rare. [2] About 20 to 25% of people develop pain at the site of injection while about 2% develop a fever. [2] There is no clear association with severe allergic reactions. [2] The Hib vaccine is available by itself, in combination with the diphtheria/tetanus/pertussis vaccine, and in combination with the hepatitis B vaccine, among others. [2] All Hib vaccines that are currently used are conjugate vaccine. [2]

An initial Hib vaccine consisting of plain (unconjugated) type b polysaccharide, was introduced in the United States in 1985. [7] but was replaced by a more effective conjugated formulations beginning in 1987. [8] As of 2013, 184 countries include it in their routine vaccinations. [2] It is on the World Health Organization's List of Essential Medicines. [9]

Medical uses

Hib conjugate vaccines have been shown to be effective against all manifestations of Hib disease, with a clinical efficacy among fully vaccinated children estimated to be between 95–100%. The vaccine has also been shown to be immunogenic in patients at high risk of invasive disease. Hib vaccine is not effective against non-type B Haemophilus influenzae. However, non-type B disease is rare in comparison to pre-vaccine rates of Haemophilus influenzae type B disease. [10]

Impact

Prior to introduction of the conjugate vaccine, Hib was a leading cause of childhood meningitis, pneumonia, and epiglottitis in the United States, causing an estimated 20,000 cases a year in the early 1980s. Nearly all disease was in children under five years old. [11] After routine use of Hib conjugate vaccines in the United States, the rate of invasive Hib disease decreased from 40–100 per 100,000 children down to fewer than 1 per 100,000. [12] Similar reductions in Hib disease occurred after introduction of the vaccine in Western Europe [13] and developing countries. [14] However, in recent years. Haemophilus influenzae strains with other encapsulated serotypes such as a or f, or non-encapsulated strains, have been recognized to cause invasive disease, particularly in high risk populations. [14]

Recommendations

The CDC and the WHO recommend that all infants be vaccinated using a polysaccharide-protein conjugate Hib vaccine, starting after the age of six weeks. The vaccination is also indicated in people without a spleen. [15]

Side effects

Clinical trials and ongoing surveillance have shown Hib vaccine to be safe. In general, adverse reactions to the vaccine are mild. The most common reactions are mild fever, loss of appetite, transient redness, swelling, or pain at the site of injection, occurring in 5–30% of vaccine recipients. More severe reactions are extremely rare.[ citation needed ]

Mechanisms of action

Polysaccharide vaccine

Haemophilus influenzae type b is a bacterium with a polysaccharide capsule; the main component of this capsule is polyribosyl ribitol phosphate (PRP). Anti-PRP antibodies have a protective effect against Hib infections. However, the antibody response to PRP was quite variable in young children, and diminished rapidly after administration. This problem was due to recognition of the PRP antigen by B cells, but not T cells. In other words, even though B cell recognition was taking place, T cell recruitment (via MHC class II) was not, which compromised the immune response. This interaction with only B cells is termed T-independent (TI). This process also inhibits the formation of memory B cells, thus compromising long term immune system memory. [16] [17]

Conjugate vaccine

PRP covalently linked to a protein carrier was found to elicit a greater immune response than the polysaccharide form of the vaccine. This is due to the protein carrier being highly immunogenic in nature. The conjugate formulations show responses which are consistent with T-cell recruitment (namely a much stronger immune response). A memory effect (priming of the immune system against future attack by Hib) is also observed after administration; indicative that memory B cell formation is also improved over that of the unconjugated polysaccharide form. Since optimal contact between B cells and T cells is required (via MHC II) to maximize antibody production, it is reasoned that the conjugate vaccine allows B cells to properly recruit T cells, this is in contrast to the polysaccharide form in which it is speculated that B cells do not interact optimally with T cells leading to the TI interaction. [16] [17]

Developing world

Introduction of Hib vaccine in developing countries lagged behind that in developed countries for several reasons. The expense of the vaccine was large in comparison to the standard EPI vaccines. Poor disease surveillance systems and inadequate hospital laboratories failed to detect the disease, leading many experts to believe that Hib did not exist in their countries. And health systems in many countries were struggling with the current vaccines they were trying to deliver.

GAVI and the Hib Initiative

In order to remedy these issues, the GAVI Alliance took active interest in the vaccine. [18] [19] [20]

History

Polysaccharide vaccine

The first Hib vaccine licensed was a unconjugated polysaccharide vaccine, called PRP. This vaccine was first marketed in the United States in 1985. [21] Similar to other unconjugated polysaccharide vaccines, serum antibody responses to PPP vaccine were highly age-dependent. Children under 18 months of age did not produce a positive response for this vaccine. As a result, the age group with the highest incidence of Hib disease was unprotected, limiting the usefulness of the vaccine. Also, post-licensure studies by Michael Osterholm [22] and his colleagues,  and Dan M. Granoff et al. [23] suggested that the PRP vaccine was largely ineffective in preventing invasive Hib disease in children 18 to 59 months, the age group recommended for vaccination . The vaccine was withdrawn from the market in 1988. [24]

Conjugate vaccine

The shortcomings of the polysaccharide vaccine led to the production of the Hib polysaccharide-protein conjugate vaccine. [21] In 1987, the first Hib conjugate vaccine, which used diphtheria toxoid as the carrier protein (PRP-D), was licensed in the U.S. and initially recommended for children ages 18 to 59 months of age. [25] This vaccine was based on work done by Lasker Award-winning American scientists John Robbins and Rachel Schneerson [26] at the U.S. National Institutes of Health, and Porter Anderson and David Smith then at Boston Children's Hospital. [27] Attaching Hib polysaccharide to a protein carrier greatly increased the ability of the immune system of young children to recognize the polysaccharide and develop immunity. In contrast to unconjugated PRP vaccine, PRP-D vaccines was highly effective in controlling Hib disease in the age group being immunized (18 to 59 months). Unexpectedly. the vaccine also was associated with a dramatic decline in Hib disease in the age group less than 18 months, which at the time was not being vaccinated (evidence of indirect community protection or “herd immunity”. [28]   Trudy Murphy and her colleagues reported that healthy children in a day care center who had been immunized with PRP-D had a lower rate of Hib colonization in their noses and throats than healthy unvaccinated children, which was not observed in children vaccinated with unconjugated PRP vaccine. [29]   These results provided an explanation for the ability of PRP-D conjugate vaccine to lower transmission of Hib from conjugate-vaccinated to unvaccinated children, and provide indirect community protection from conjugate vaccination .

There are currently three types of conjugate vaccine, utilizing different carrier proteins for the conjugation process: inactivated tetanospasmin (also called tetanus toxoid); mutant diphtheria protein; and meningococcal group B outer membrane protein. [16] The Hib vaccine using a meningococcal outer membrane carrier protein has unique immunostimulatory properties, eliciting an anticapsular response to a single injection given to infants as young as 2 months of age. [30] In contrast, Hib conjugate vaccines using other protein carriers require two or three injections to reliably elicit anticapsular antibody responses in infants less than six months of age. [31]

Combination vaccines

Multiple combinations of Hib and other vaccines have been licensed in the United States, reducing the number of injections necessary to vaccinate a child. Hib vaccine combined with diphtheria-tetanus-pertussispolio vaccines and hepatitis B vaccines are available in the United States. The World Health Organization (WHO) has certified several Hib vaccine combinations, including a pentavalent diphtheria-pertussis-tetanus-hepatitis B-Hib, for use in developing countries. There is not yet sufficient evidence on how effective this combined pentavalent vaccine is in relation to the individual vaccines. [32]

Related Research Articles

ATC code J07Vaccines is a therapeutic subgroup of the Anatomical Therapeutic Chemical Classification System, a system of alphanumeric codes developed by the World Health Organization (WHO) for the classification of drugs and other medical products. Subgroup J07 is part of the anatomical group J Antiinfectives for systemic use.

<span class="mw-page-title-main">DPT vaccine</span> Combination vaccine

The DPT vaccine or DTP vaccine is a class of combination vaccines to protect against three infectious diseases in humans: diphtheria, pertussis, and tetanus (lockjaw). The vaccine components include diphtheria and tetanus toxoids, and either killed whole cells of the bacterium that causes pertussis or pertussis antigens. The term toxoid refers to vaccines which use an inactivated toxin produced by the pathogen which they are targeted against to generate an immune response. In this way, the toxoid vaccine generates an immune response which is targeted against the toxin which is produced by the pathogen and causes disease, rather than a vaccine which is targeted against the pathogen itself. The whole cells or antigens will be depicted as either "DTwP" or "DTaP", where the lower-case "w" indicates whole-cell inactivated pertussis and the lower-case "a" stands for "acellular". In comparison to alternative vaccine types, such as live attenuated vaccines, the DTP vaccine does not contain any live pathogen, but rather uses inactivated toxoid to generate an immune response; therefore, there is not a risk of use in populations that are immune compromised since there is not any known risk of causing the disease itself. As a result, the DTP vaccine is considered a safe vaccine to use in anyone and it generates a much more targeted immune response specific for the pathogen of interest.

<i>Haemophilus influenzae</i> Species of bacterium

Haemophilus influenzae is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37 °C.

<span class="mw-page-title-main">Conjugate vaccine</span> Type of vaccine

A conjugate vaccine is a type of subunit vaccine which combines a weak antigen with a strong antigen as a carrier so that the immune system has a stronger response to the weak antigen.

<span class="mw-page-title-main">Childhood immunizations in the United States</span>

The schedule for childhood immunizations in the United States is published by the Centers for Disease Control and Prevention (CDC). The vaccination schedule is broken down by age: birth to six years of age, seven to eighteen, and adults nineteen and older. Childhood immunizations are key in preventing diseases with epidemic potential.

<span class="mw-page-title-main">Pneumococcal vaccine</span> Vaccine to prevent infection by the bacteria Stretococcus pneumoniae

Pneumococcal vaccines are vaccines against the bacterium Streptococcus pneumoniae. Their use can prevent some cases of pneumonia, meningitis, and sepsis. There are two types of pneumococcal vaccines: conjugate vaccines and polysaccharide vaccines. They are given by injection either into a muscle or just under the skin.

<span class="mw-page-title-main">Hepatitis B vaccine</span> Vaccine against hepatitis B

Hepatitis B vaccine is a vaccine that prevents hepatitis B. The first dose is recommended within 24 hours of birth with either two or three more doses given after that. This includes those with poor immune function such as from HIV/AIDS and those born premature. It is also recommended that health-care workers be vaccinated. In healthy people, routine immunization results in more than 95% of people being protected.

John Bennett Robbins was a senior investigator at the National Institutes of Health (NIH), best known for his contribution to the development of the vaccine against bacterial meningitis Hib)) with his colleague Rachel Schneerson. He conducted research on the Bethesda, Maryland campus of the NIH from 1970 until his retirement at the age of 80 in 2012. During his tenure, he worked in the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and the Food and Drug Administration’s biologics laboratories on location.

<span class="mw-page-title-main">Pertussis vaccine</span> Vaccine protecting against whooping cough

Pertussis vaccine is a vaccine that protects against whooping cough (pertussis). There are two main types: whole-cell vaccines and acellular vaccines. The whole-cell vaccine is about 78% effective while the acellular vaccine is 71–85% effective. The effectiveness of the vaccines appears to decrease by between 2 and 10% per year after vaccination with a more rapid decrease with the acellular vaccines. The vaccine is only available in combination with tetanus and diphtheria vaccines. Pertussis vaccine is estimated to have saved over 500,000 lives in 2002.

Meningococcal vaccine refers to any vaccine used to prevent infection by Neisseria meningitidis. Different versions are effective against some or all of the following types of meningococcus: A, B, C, W-135, and Y. The vaccines are between 85 and 100% effective for at least two years. They result in a decrease in meningitis and sepsis among populations where they are widely used. They are given either by injection into a muscle or just under the skin.

Haemophilus meningitis is a form of bacterial meningitis caused by the Haemophilus influenzae bacteria. It is usually associated with Haemophilus influenzae type b. Meningitis involves the inflammation of the protective membranes that cover the brain and spinal cord. Haemophilus meningitis is characterized by symptoms including fever, nausea, sensitivity to light, headaches, stiff neck, anorexia, and seizures. Haemophilus meningitis can be deadly, but antibiotics are effective in treating the infection, especially when cases are caught early enough that the inflammation has not done a great deal of damage. Before the introduction of the Hib vaccine in 1985, Haemophilus meningitis was the leading cause of bacterial meningitis in children under the age of five. However, since the creation of the Hib vaccine, only two in every 100,000 children contract this type of meningitis. Five to ten percent of cases can be fatal, although the average mortality rate in developing nations is seventeen percent, mostly due to lack of access to vaccination as well as lack of access to medical care needed to combat the meningitis.

A Vaccine Information Statement (VIS) is a document designed by the Centers for Disease Control and Prevention (CDC) to provide information to a patient receiving a vaccine in the United States. The National Childhood Vaccine Injury Act requires that medical professionals provide a VIS to patients before receiving certain vaccinations. The VIS includes information about the vaccine's benefits and risks, a description of the vaccine, indications and contraindications, instructions for patients experiencing an adverse reaction, and additional resources.

<span class="mw-page-title-main">Tetanus vaccine</span> Vaccines used to prevent tetanus

Tetanus vaccine, also known as tetanus toxoid (TT), is a toxoid vaccine used to prevent tetanus. During childhood, five doses are recommended, with a sixth given during adolescence.

CRM197 is a non-toxic mutant of diphtheria toxin, currently used as a carrier protein for polysaccharides and haptens to make them immunogenic. There is some dispute about the toxicity of CRM197, with evidence that it is toxic to yeast cells and some mammalian cell lines.

DTaP-IPV/Hib vaccine is a 5-in-1 combination vaccine that protects against diphtheria, tetanus, whooping cough, polio, and Haemophilus influenzae type B.

DPT-Hib vaccine is a combination vaccine whose generic name is diphtheria and tetanus toxoids and whole-cell pertussis vaccine adsorbed with Hib conjugate vaccine, sometimes abbreviated to DPT-Hib. It protects against the infectious diseases diphtheria, tetanus, pertussis, and Haemophilus influenzae type B.

DTaP-Hib vaccine is a combination vaccine whose generic name is diphtheria and tetanus toxoids and acellular pertussis adsorbed with Haemophilus B conjugate vaccine, sometimes abbreviated to DTaP-Hib. It protects against the infectious diseases diphtheria, tetanus, pertussis, and Haemophilus influenzae type B.

<span class="mw-page-title-main">Hexavalent vaccine</span> Single vaccine protecting against six individual diseases

A hexavalent vaccine, or 6-in-1 vaccine, is a combination vaccine with six individual vaccines conjugated into one, intended to protect people from multiple diseases. The term usually refers to the children's vaccine that protects against diphtheria, tetanus, pertussis, poliomyelitis, haemophilus B, and hepatitis B, which is used in more than 90 countries around the world including in Europe, Canada, Australia, Jordan, and New Zealand.

Trudy Virginia Noller Murphy is an American pediatric infectious diseases physician, public health epidemiologist and vaccinologist. During the 1980s and 1990s, she conducted research at Southwestern Medical School in Dallas, Texas on three bacterial pathogens: Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (pneumococcus), and methicillin-resistant Staphylococcus aureus (MRSA). Murphy's studies advanced understanding of how these organisms spread within communities, particularly among children attending day care centers. Her seminal work on Hib vaccines elucidated the effects of introduction of new Hib vaccines on both bacterial carriage and control of invasive Hib disease. Murphy subsequently joined the National Immunization Program at the Centers for Disease Control and Prevention (CDC) where she led multi-disciplinary teams in the Divisions of Epidemiology and Surveillance and The Viral Hepatitis Division. Among her most influential work at CDC was on Rotashield™, which was a newly licensed vaccine designed to prevent severe diarrheal disease caused by rotavirus. Murphy and her colleagues uncovered that the vaccine increased the risk of acute bowel obstruction (intussusception). This finding prompted suspension of the national recommendation to vaccinate children with Rotashield, and led the manufacturer to withdraw the vaccine from the market. For this work Murphy received the United States Department of Health and Human Services Secretary's Award for Distinguished Service in 2000, and the publication describing this work was recognized in 2002 by the Charles C. Shepard Science Award from the Centers for Disease Control and Prevention.

Dan M. Granoff is an infectious disease physician-scientist who was named the 2014 Maurice Hilleman/Merck Laureate by the American Society for Microbiology for outstanding contributions to vaccine discovery and development. Beginning in 2011, Granoff held the Clorox Foundation Endowed Chair and was director of the Center of Immunobiology and Vaccine Development at Children's Hospital Oakland Research Institute. His work increased understanding of basic mechanisms of human immunity to encapsulated bacteria, and furthered development of vaccines against Haemophilus influenzae type B (Hib) and Neisseria meningitidis.

References

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Further reading